1. Field of the Invention
This invention relates to an improved bag evacuation valve, and more particularly to such a valve which can be used with evacuation devices having suction nozzles of widely differing diameter, and which does not damage any other, for example, tightly closed bag stacked on its outside or placed adjacent to it, while allowing bags stacked on or adjacent to one another to form a flat and stable shape of packing.
2. Description of the Related Art
As a bag for holding its contents by keeping them from the ambient air, there is known, for example, a tightly closed and compressed bag from which air is forced out by suction to reduce its volume as evacuated and the volume of its contents (if compressible). A compressed and tightly closed bag will hereinafter be referred to simply as a “tightly closed bag” unless any particular necessity to the contrary arises.
A tightly closed bag as mentioned above is sometimes equipped with a valve mechanism for keeping its inside and outside from each other so that when air has been forced out from its inside by suction, a negative pressure prevailing in its inside may not allow air to flow in from its outside as known, for example from Japanese Patent JP-A-6-227551 and JP-UM-A-4-132043.
According to the above documents, however, a tightly closed bag has a connector projecting from its valve mechanism mounting side for connecting the nozzle of a suction device, and it produces inconveniences as pointed out below. More specifically, the known valve mechanism has a problem in that the diameter (or shape) of the suction device nozzle does not suit the shape of the connector projecting from the valve mechanism mounting side.
Moreover, it is likely to result from the projection of the connector from the valve mechanism mounting side of a tightly closed bag that when tightly closed bags holding their contents are stacked on one another, the load of an upper bag may be concentrated on the projecting portion of a lower bag and the resulting stress may damage the contents of the upper bag. Furthermore, it has been likely that stacked bags may not form a flat shape of packing, but may make an inclined shape formed by the gradual elevation of their valve mechanism mounting portions, making it impossible to stack many tightly closed bags holding their contents on one another.
Moreover, it has been likely that the connector projecting from the valve mechanism mounting side of one tightly closed bag may interfere with another tightly closed bag, for example, stacked as mentioned above and damage it.